Steam engine valve gear



STEAM ENGINE VALVE GEAR Filed Jan.- 12, 1929 INVENTOR.

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' cylinderhas a constant lead and opens the Patented May 26, 1931 UNITED STATES PATENT OFFICE J'OSElI-I OLSON, OF HOUSTON, TEXAS STEAM ENGINE VALVE GEAR Application filed January 12, 1929. Serial No. 332,171.

and improved .means for controlling the valve lead. In valve gears of the type now inmost common use, the valve controlling the admission of steam Into the engine steam passageway to the cylinders a little before the piston reaches the end of its travel at each end of the cylinder. This renders the engine more efficient while running, but makes it mode difficult to start, in that thepiston at the end of its stroke must work against the pressure of the steam so admitted. It is among the objects of this invention to provide a valve gear of the character described and of such construction that the lead of the valve may be varied and the admission of steam' into the cylinder controlled to the end'that when the engine is starting or running at slow speed the steam may be admitted when'the piston is on dead center, and after the engine has speeded upthelead of the valve may be increased to admit steam to the cylinder befor the piston has reached the end of its stroke. I

' With the above and other objects in view, the nature of which appear from the following description, this invention has particular relation to certain novel features of construction, operation and combination of parts, an example of which is given in this cylinder and the numeral 2 designates the valve casing associated therewith. The cylinder has the usual piston to whichis connected the piston rod 3, and in the valve casing 2 there is the usual valve to which there is connected the valve stem or rod 4. The outer end of the piston rod 3 is connected to the cross head 5, which runs in the track 6, and has its power transmitted by means of the usual driving arm 7 to the driving wheels 7 for the purpose of driving the latter.

One of the driving wheels 7 has an eccentric wrist pin 8 to which is fixed the eccentric crank 9, to the free end of which is pivoted the eccentric rod 10. The other end of this rod 10 is pivoted to the lower end of the link 11, which is pivoted for oscillation about the bearing 11 in the bracket 12, and whose upper end has the arcuate slot 13.

The numeral lt designates the reverse lever. end to this lever and its other end is pivoted to one arm 16 of the tumbler shaft 17. The other arm 18 of the tumbler shaft has its free end connected to the rear end of the radius bar or rod 19 through the radius rod hanger 20. This radius rod hanger is pivotally connected at its ends to the arm 18and the radius rod 19 The radius rod 19 is adapted to work along the side of the link 11 and is pivotally connected to a sliding block 21 which moves in slot 13 of the link 11.

Depending from the cross head 5 is a cross head arm 22, and the lower end of this arm is connected to the variable transmission lever 23 through the link 24, the connections between the link 24: and the arm 22 and lever 23 being. pivotal.

The lap and lead lever is pivotally connected to the variable transmission lever at a point 36 intermediate the ends of the latter, and the lap and lead lever 35 is also pivotally connected, as shown in Figs. 1 and 2, to the radius rod 19, and at an intermediate point to the valve rod &.

The variable transmission lever23 comprises two partstO and t1, the part 40 slidably engages and surrounds the upper por- A reach rod 15 is pivoted at one 7 tion of the part 11. Raising the part 40 increases the length of the lever 23. The numeral 42 indicates the longitudinal opening in the part 410 of the lever 28 within which the part 1-1 slides. The upper end of the part is provided with a yoke 16 (see Fig. 2), and within this yoke is pivotally connected the raising or lowering lever 47 for the part of the extendible transmission lever 23.

The raising or lowering lever 47 is also pivoted at 48 to the bracket 49 attached to a fixed part of the locomotive. The lever 1? is adapted to be raised by means oi? the reverse lever 1 1 acting through the reach rod 15, arm 16, link 50, sliding sleeve 51 and arm The arm 52 is pivoted to the bracket 4-9 at the point 53, and may be adapted to swing along the side of this bracket. The other end of the arm 52 is pivotally connected at 5 1 to the link 50, the latter in turn being pivotally connected at 55 to the arm 16 upon the tumbler shaft 17. Arm is pivotally connected to the sleeve 51 which is adapted to slide along the lever 17 when the lever 14L is actuated either to reverse, center or forward.

When the reversing lever 14 is moved .from the forward position, as shown in Fig. 1, the raising or lowering lever t? rises until the pivotal connection between block 21 and the radius rod 19 is on a line with the axis of oscillation of link 11. In this position the arm 17 and sleeve 51 occupy their highest position and further motion of the reversing lever 14: into reverse causes the arm -17 to descend. The raising of arm 17 causes the transmission lever to be extended, and when this occurs, the motion of the cross head 5, acting through link 24, will increase the lead of the valve, by virtue of the fact that the point 36 swings along an are which is greater than the are d ribed by the point 36 before the transn'ns on lever was extended. Similarly shortening the transmission lever 23 causes a decrease of the lead of the valve.

' hen the reverse lever is thrown completely into reverse, that is when the sliding block 21 is drawn to its uppermost position in slot 13 of the link 11, the arm i7, will occupy substantially the same position as when the lever 14 is thrown completely into forward. It the lever 14 is then actuated from the reverse position towards center, the part 420 of the transmission lever 23 will likewise be raised, whereby lead will be imparted to 'the valve while the locomotive is moving in reverse. The means described therefore permit lead to be imparted to the valve when the motion is forward or in reverse.

The travel of the steam valve is also influenced, in the usual way, by the driving wheel t through the eccentric crank 9, eccentric rod 10, the link 11, radius rod 19 and lap and lead lever 35, the travel of the valve being governed by the position of the sliding block 21 in the arcuate slot 13. When the position of the reverse lever 14 is on center the sliding block 21 is in line with the pivotal support of the link 11 in the bracket 12. In such position it is obvious that no rocking motion will be imparted to the radius rod 19 and that the valve will be operated only from the motion of the crosshead 5.

When the part 40 of the extendible transmission lever 23 is in its lowermost position, that is when the transmission lever is reduced to its shortest length, the valve is operating under zero lead or any lead for which it has been set. Raising or lowering of the block 21 in the slot 13 of the link 11 by means of the reverse lever 14 causes a simultaneous corresponding motion of extension or contraction of the length of the transmission lever, and hence a simultaneous adjustment of the lead of the valve and of the valve travel is attainable.

lVhile the invention has been described in connection with an inside admission valve connected to the valve stem 4:, an outside admission valve may be employed, in which event the radius rod 19 is connected to the lap and lead lever 35 at a point between the point 36 and the connection of the valve stem with the lap and lead lever, as will be understood by the person skilled. in the art, and as shown in Figure 8.

Having described my invention, I claim:

1. In a steam engine having a piston, a piston cross head connected to the piston, a radius bar and a controlling valve and valve rod, the combination of an extendable transmission lever connected at one end througha link with the cross head, the said extendible transmission lever having relatively moving parts for extending the length of the same and operated from the reversing lever of said engine, a lap and lead lever pivoted at one end to the transmission lever at an intermediate point, said radius bar and valve rod being pivotally connected, one to the other end of said lap and lead leverand the other to said lap and lead lever at an intermediate point of said lap and lead lever.

2. In a steam engine having a piston, a piston cross head connected to the piston, a radius bar and a controlling valve and valve rod, the combination of an extendible transmission lever connected at one end through a link with the cross head, a lap and lead lever pivoted at one end to the transmission lever at an intermediate point, said radius bar and valve rod being pivotally connected, one to the other end of said lap and lead lever and the other to said lap and lead lever at an intermediate point of said lap and lead lever, and means for extending the length of said transmission lever.

3. In a steam engine having a piston, a

piston cross head connected to the piston, a V

radius bar and a controlling valve and valve rod, the combination of a transmission lever connected at one end through a link with the cross head, a lap and lead lever pivoted at one end to the transmission lever at an intermediate point, said radius bar and valve rod being pivotally connected, one to the other end of said lap and lead lever and the other to said lap and lead lever at an intermediate point of said lap and lead lever, and means for increasing or decreasing the are described by the point of connection of the lap and lead lever with the transmission lever for increasing or decreasing the lead of said valve whether the engine is in motion or at rest.

4. In a steam engine havinga piston, a piston cross head connected to the piston, a radius bar and controlling valve and valve rod, the combination of an extendible transmission lever connected at one end with the cross head, the said extendible transmission I lever having relatively moving parts for extending the length of the same, a lever connected with one of said relatively movable parts, a slidable member engaging said last mentioned lever, means for sliding said slidable member along said lever to lift and lower said lever to adjust the length of said extendible transmission lever, a lap and lead lever pivoted at one end to the transmission lever at an intermediate point, said radius bar and valve rod being pivotally connected, one to the other end of said lap and lead lever and the other to said lap and lead lever at an intermediate point of said lap and lead lever.

In testimony whereof I afiix my signature.

JOSEPH OLSON. 

